"He's got some elbow stiffness, tightness," D-backs GM Dave Stewart said. "So the thing to do was shut him down. Any time it's an elbow, it's a concern for me. I don't know that organizationally I can speak for everybody, but for me when any of our players complain about elbow stiffness or tightness and you can't make your turn that's a concern for me."
Lopez cost the D-backs more than $16 million to sign last winter because they went over their international signing pool and were forced to pay a 100 percent penalty tax on the $8.27 million bonus.
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.